Supervisor Due Diligence in Plain Language

What Due Diligence Actually Means

Due diligence is a legal standard under Ontario's Occupational Health and Safety Act — specifically found in Section 66 — that supervisors and employers can rely on as a defence when charged with a violation. In plain terms, it means taking every reasonable precaution in the circumstances to protect workers. If you can demonstrate that you took those precautions, you have a defence against conviction, even when something goes wrong on site.

The Test Courts Apply

When a supervisor is charged under the OHSA, courts apply an objective standard: what would a reasonably competent supervisor in the same circumstances have known, and what would they have done about it? This is not a perfection standard — it adjusts for what was foreseeable, what was known at the time, and what authority the supervisor had to act. A supervisor who genuinely could not have known about a hazard is treated differently from one who knew and did nothing.

What Every Reasonable Precaution Looks Like in Practice

The following are the kinds of actions that build and demonstrate due diligence on the ground:

• Conducting a hazard assessment before work begins — identifying what could go wrong and taking steps to address it before the crew starts
• Ensuring workers are trained and competent for the specific task they are assigned, not just for their trade in general
• Providing and confirming the use of appropriate personal protective equipment before and during the work
• Correcting unsafe conditions immediately when identified — not flagging them for a later shift or the next inspection
• Stopping work when a hazard cannot be immediately controlled — this is an obligation under Section 27, not just a right
• Communicating safety information clearly before work starts through toolbox talks, direct instruction, or both

Common Mistakes That Undermine Due Diligence

• Assuming workers know what to do because they have performed the task before — competency must be verified, not assumed
• Treating safety documentation as a substitute for safety action — records prove diligence, but the action has to come first
• Delegating hazard identification without confirming it was actually completed
• Allowing production pressure to delay hazard correction — pace and schedule do not override legal obligations
• Failing to document what was done when a concern was identified and addressed
• Relying on verbal instructions alone without following up to confirm worker understanding

Documentation: What to Record and Why

Documentation does not create due diligence — it proves it. The actual due diligence is the consistent, reasonable action taken before and during work. But if something goes wrong and there is no record of what was done, it becomes very difficult to demonstrate that those actions occurred. A Ministry of Labour investigation will ask what steps were taken. Documentation turns invisible daily habits into a visible, verifiable record. The time to create that record is before the incident, not after.

What Supervisors Should Document

• Pre-shift hazard assessments: what was identified, what was corrected, and the date and time
• Toolbox talks: the topic covered, the date and location, and names or signatures of workers present
• Equipment inspections: what was checked, results, and any deficiencies found along with how they were addressed
• Competency confirmations: evidence that workers received task-specific training and were observed performing it correctly
• Corrective actions: the hazard identified, the action taken, who was responsible, and the completion date